Neurology Watch News Blog From Medicineworld.Org

December 28, 2011, 7:08 PM CT

Diet, nutrient levels linked to cognitive ability, brain shrinkage

Omega-3

New research has observed that elderly people with higher levels of several vitamins and omega 3 fatty acids in their blood had better performance on mental acuity tests and less of the brain shrinkage typical of Alzheimer's disease � while "junk food" diets produced just the opposite result.

The study was among the first of its type to specifically measure a wide range of blood nutrient levels instead of basing findings on less precise data such as food questionnaires, and found positive effects of high levels of vitamins B, C, D, E and the healthy oils most usually found in fish.

The research was done by researchers from the Oregon Health and Science University in Portland, Ore., and the Linus Pauling Institute at Oregon State University. It was published recently in Neurology, the medical journal of the American Academy of Neurology.

"This approach clearly shows the biological and neurological activity that's linked to actual nutrient levels, both good and bad," said Maret Traber, a principal investigator with the Linus Pauling Institute and co-author on the study.

"The vitamins and nutrients you get from eating a wide range of fruits, vegetables and fish can be measured in blood biomarkers," Traber said. "I'm a firm believer these nutrients have strong potential to protect your brain and make it work better".........

Fast prediction of axon behavior

Scientists at Case Western Reserve University have developed a computer modeling method to accurately predict how a peripheral nerve axon responds to electrical stimuli, slashing the complex work from an inhibitory weeks-long process to just a few seconds.

The method, which enables efficient assessment of a nerve's response to millions of electrode designs, is an integral step toward building more accurate and capable electrodes to stimulate nerves and thereby enable people with paralysis or amputated limbs better control of movement.

To increase the accuracy of the results, the scientists included a key parameter overlooked in past mathematical approaches that were equally fast, but inaccurate. With the new techniques, electrode design can be optimized using advanced algorithms based on natural genetics.

An explanation of the work, which the team hopes others in the field will freely use, and a second method that was simpler and faster but proved less effective, are now available online in the Journal of Neural Engineering

"We believe this will allow the next generation of computer-aided development of electrodes," said Dustin Tyler, associate professor of biomedical engineering at Case School of Engineering and senior author of the paper.........

Link Between Parkinson's and Pesticides

Zezong Gu, right, MD, PhD, assistant professor of pathology and anatomical sciences at MU, and Fajun Meng, an MU visiting scholar, examine a model of parkin clusters. Their research yields new details about how parkin proteins and pesticides contribute to Parkinson's disease. After Alzheimer's disease, Parkinson's disease is the most common neurodegenerative disorder.

In a new article reported in the journal Molecular Neurodegeneration, scientists at the University of Missouri School of Medicine take some of the first steps toward unraveling the molecular dysfunction that occurs when proteins are exposed to environmental toxins. Their discovery helps further explain recent NIH findings that demonstrate the link between Parkinson's disease and two particular pesticides - rotenone and paraquat.

"Fewer than 5 percent of Parkinson's cases are attributed to genetics, but more than 95 percent of cases have unknown causes," said Zezong Gu, MD, PhD, assistant professor of pathology and anatomical sciences. "This study provides the evidence that oxidative stress, possibly due to sustained exposure to environmental toxins, may serve as a primary cause of Parkinson's. This helps us begin to unveil why a number of people, such as farmers exposed to pesticides, have an increased occurence rate of the disease."

Researchers previously understood that Parkinson's is linked to oxidative stress, which is when electronically unstable atoms or molecules damage cells. The MU study yields more specific information about how oxidative stress causes parkin, a protein responsible for regulating other proteins, to malfunction.

These findings come as the result of collaborative research conducted by Gu and the paper's primary author, Fanjun Meng, an MU visiting scholar from the Chinese Academy of Sciences Beijing Institute of Genomics, as well as colleagues at the Sanford-Burnham Medical Research Institute and the University of California at San Diego. The article also represents the first published work from scientists at the new MU Center for Translational Neuroscience.........

Stem cell model offers clues to cause of inherited ALS

An international team of researchers led by scientists at the University of California, San Diego School of Medicine have used induced pluripotent stem cells (iPSCs) derived from patients with amyotrophic lateral sclerosis (ALS) to reveal for the first time how reduced levels of a specific protein may play a central role in causing at least one inherited form of the disease.

The work, reported in the June 2011 online issue of the journal Human Molecular Genetics, could help researchers overcome a major hurdle in the study and therapy of ALS, an incurable neuromuscular disorder also known as Lou Gehrig's disease. ALS is universally fatal, with a median age of onset of 55 years and survival of two to five years after symptoms appear. Past research efforts have long been stymied by difficulties in translating successful drug tests in animal models of ALS to humans.

"There is an urgent need for ALS human models that can be translated into clinical trials to verify therapeutic targets in the human genetic background," said Alysson R. Muotri, PhD, assistant professor in the UCSD Departments of Pediatrics and Cellular and Molecular Medicine, and one of the study's senior authors. "Rodents have been used in the past and still have a critical impact in unveiling the complexity of ALS, but the vast majority of drugs that have demonstrated efficacy in rodent models have not done the same in preclinical and clinical human trials".........

Source of key brain function

Researchers at the University of Southern California have pinned down the region of the brain responsible for a key survival trait: our ability to comprehend a scene�even one never previously encountered�in a fraction of a second.

The key is to process the interacting objects that comprise a scene more quickly than unrelated objects, as per corresponding author Irving Biederman, professor of psychology and computer science in the USC Dornsife College and the Harold W. Dornsife Chair in Neuroscience.

The study appears in the June 1 issue of The Journal of Neuroscience

The brain's ability to understand a whole scene on the fly "gives us an enormous edge on an organism that would have to look at objects one by one and slowly add them up," Biederman said. What's more, the interaction of objects in a scene actually allows the brain to identify those objects faster than if they were not interacting.

While prior research had already established the existence of this "scene-facilitation effect," the location of the part of the brain responsible for the effect remained a mystery. That's what Biederman and main author Jiye G. Kim, a graduate doctoral student in Biederman's lab, set out to uncover with Chi-Hung Juan of the Institute of Cognitive Neuroscience at the National Central University in Taiwan.........

Snapshots of Huntington's disease protein

Scientists at the Department of Energy's Oak Ridge National Laboratory and the University of Tennessee have for the first time successfully characterized the earliest structural formation of the disease type of the protein that causes Huntington's disease. The incurable, hereditary neurological disorder is always fatal and affects one in 10,000 Americans.

Huntington's disease is caused by a renegade protein "huntingtin" that destroys neurons in areas of the brain concerned with the emotions, intellect and movement. All humans have the normal huntingtin protein, which is known to be essential to human life, eventhough its true biological functions remain unclear.

Christopher Stanley, a Shull Fellow in the Neutron Scattering Science Division at ORNL, and Valerie Berthelier, a UT Graduate School of Medicine researcher who studies protein folding and misfolding in Huntington's, have used a small-angle neutron scattering instrument, called Bio-SANS, at ORNL's High Flux Isotope Reactor to explore the earliest aggregate species of the protein that are thought to bethe most toxic.

Stanley and Berthelier, in research published recently in Biophysical Journal, were able to determine the size and mass of the mutant protein structures―from the earliest small, spherical precursor species composed of two (dimers) and three (trimers) peptides―along the aggregation pathway to the development of the resulting, later-stage fibrils. They were also able to see inside the later-stage fibrils and determine their internal structure, which provides additional insight into how the peptides aggregate.........

The brain performs visual search near optimally

In the wild, mammals survive because they can see and evade predators lurking in the shadowy bushes.

That ability translates to the human world. Transportation Security Administration screeners can pick out dangerous objects in an image of our messy and stuffed suitcases. We get out of the house every morning because we find our car keys on that cluttered shelf next to the door.

This ability to recognize target objects surrounded by distracters is one of the remarkable functions of our nervous system.

"Visual search is an important task for the brain. Surprisingly, even in a complex task like detecting an object in a scene with distracters, we find that people's performance is near optimal. That means that the brain manages to do the best possible job given the available information," said Dr. Wei Ji Ma. A report on research by him and his colleagues from other institutions appears online in the journal Nature Neuroscience

Recognizing the target is more than figuring out each individual object.

"Target detection involves integrating information from multiple locations," said Ma. "A number of objects might look like the target for which you are searching. It is a cognitive judgment as well as a visual one".

One factor that must be taken into account is reliability of the information.........

Parkinson's disease and prostate cancer

University of Utah School of Medicine scientists have found compelling evidence that Parkinson's disease is linked to an increased risk of prostate cancer and melanoma, and that this increased cancer risk also extends to close and distant relatives of individuals with Parkinson's disease. Eventhough a link between Parkinson's disease and melanoma has been suspected before, this is the first time that an increased risk of prostate cancer has been reported in Parkinson's disease.

Parkinson's disease (PD) is a progressive neurologic condition that leads to tremors and difficulty with walking, movement, and coordination. Most studies demonstrate that individuals with PD have an overall decreased rate of cancer, with the notable exception of melanoma, the most serious form of skin cancer. Prior research has suggested a possible genetic link between PD and melanoma, but these studies have been limited to first-degree relatives who often share a similar environment, making it difficult to distinguish between genetic and environmental risk factors.

"Neurodegenerative disorders such as Parkinson's disease may share common disease-causing mechanisms with some cancers," says Stefan-M. Pulst, MD, professor and chair of the department of neurology, at the University of Utah, and co-author on this study. "Using the Utah Population Database, we were able to explore the association of PD with different types of cancer by studying cancer risk in individuals with PD, as well as their close and distant relatives".........

Nurturing newborn neurons

More newborn neurons (light green blotches near orange areas) are visible in part of the hippocampus of an adult mouse in which neurogenesis was genetically enhanced (right) than in a control mouse (left) .

Credit: Amar Sahay, Ph.D., Columbia University

Adult mice engineered to have more newborn neurons in their brain memory hub excelled at accurately discriminating between similar experiences � an ability that declines with normal aging and in some anxiety disorders. Boosting such neurogenesis in the adult hippocampus also produced antidepressant-like effects when combined with exercise, in the study funded by the National Institutes of Health.

Researchers, for the first time, pinpointed the effects of enhanced adult neurogenesis by creating mice lacking a gene mandatory for programmed cell death of newborn neurons in the adult hippocampus.

"These mice with more young neurons were better at recognizing patterns � tasks that become more challenging as we age," explained Rene Hen Ph.D., of Columbia University in New York City. "A deficit in this ability can also contribute to anxiety, as over-generalization sometimes leads to mistaking ambiguous cues as threatening. Our study demonstrates that the stimulation of adult neurogenesis is sufficient to improve such pattern recognition behavior, but, while necessary, not sufficient to lift depression-like behavior."

Hen and Amar Sahay, Ph.D., grantees of the NIH's National Institute of Mental Health (NIMH), and his colleagues, report on their discovery online April 3, 2011, in the journal Nature........

4 new genes identified for Alzheimer's

Mount Sinai School of Medicine scientists are part of a consortium that has identified four new genes that when present increase the risk of a person developing Alzheimer's disease during the later part of life. The findings are reported in the current issue of Nature Genetics. The consortium also contributed to the identification of a fifth gene reported by other groups of researchers from the United States and Europe.

"Mount Sinai has unique resources that we contributed to the study, having one of the largest brain banks for Alzheimer samples in the world," said lead Mount Sinai scientist, Joseph Buxbaum, PhD, Professor of Psychiatry, Neuroscience, and Genetics and Genomic Sciences at Mount Sinai School of Medicine. "Follow up studies of the genes identified, to determine how they affect brain biochemistry, are now possible in our samples, and this can help us understand how the genes contribute to Alzheimer's disease".

The study, conducted by the Alzheimer's Disease Genetics Consortium, consisting of researchers from 44 universities and research institutions in the United States, and led by Gerard D. Schellenberg, PhD, at Penn, with primary analysis sites at Miami, led by Margaret A. Pericak-Vance, PhD, and Boston, led by Lindsay A. Farrer, PhD,.........

Sleep during adolescence

Eventhough adolescents need just as much sleep as younger children, sleep times decrease over the course of development, leaving a number of teens chronically sleep-deprived. Studies have consistently indicated that insufficient sleep can have a negative effect on a number of aspects of adolescents' lives, leading to mood disturbances, poorer physical health, and academic difficulties. But few studies have examined how sleep affects the ways adolescents function on a daily basis or how the effects of sleep change over time.

The Society for Research in Child Development (SRCD) will host a symposium during its Biennial Meeting at which scientists will consider the effects of sleep on adolescents. All of the papers that will be presented look at day-to-day variation in adolescents' sleep by using daily diaries, and consider how sleep patterns are related not only to concurrent well-being but also to outcomes later in development.

Among the questions that will be addressed:

How do nightly variations in teenagers' sleep affect their experiences the following day? In turn, do daily experiences one day affect sleep the next night?

What are the delayed effects of sleep (or lack of sleep)? For example, does insufficient sleep in one year lead to problems in later years?........

Migraine headaches and a common heart defect

Cincinnati, OH, March 31, 2011 -- Roughly 15% of children suffer from migraines, and approximately one-third of these affected children have migraines with aura, a collection of symptoms that can include weakness, blind spots, and even hallucinations. Eventhough the causes of migraines are unclear, a newly released study soon to be published in The Journal of Pediatrics suggests a correlation between migraine headaches in children and a heart defect called patent foramen ovale, which affects 25% of people in the U.S.

Dr. Rachel McCandless and his colleagues from the Primary Children's Medical Center and the University of Utah studied children 6-18 years old who were diagnosed with migraines between 2008 and 2009. The 109 children enrolled in the study were treated at the Primary Children's Medical Center, which serves kids from Utah, Idaho, Montana, Nevada, Colorado, and parts of Wyoming.

The scientists took two-dimensional echocardiograms of each child's heart, looking for a patent foramen ovale (PFO), a common defect in the wall between the two upper chambers of the heart. Eventhough a PFO is not necessarily dangerous, it can allow unfiltered blood to bypass the lungs and circulate throughout the body. As Dr. McCandless explains, "Some adult studies have suggested a link between having a PFO and migraine headaches".........

Activity of single neurons during seizures

Single neuron

Typically the first study to examine the activity of hundreds of individual human brain cells during seizures has observed that seizures begin with extremely diverse neuronal activity, contrary to the classic view that they are characterized by massively synchronized activity. The investigation by Massachusetts General Hospital (MGH) and Brown University scientists also observed pre-seizure changes in neuronal activity both in the cells where seizures originate and in nearby cells. The report will appear in Nature Neuroscience and is receiving advance online publication.

"Our findings suggest that different groups of neurons play distinct roles at different stages of seizures," says Sydney Cash, MD, PhD, of the MGH Department of Neurology, the paper's senior author. "They also indicate that it appears to be possible to predict impending seizures, and that clinical interventions to prevent or stop them probably should target those specific groups of neurons."

Epileptic seizures have been reported since ancient times, and today 50 million individuals worldwide are affected; but much remains unknown about how seizures begin, spread and end. Current knowledge about what happens in the brain during seizures largely comes from EEG readings, which reflect the average activity of millions of neurons at a time. This study used a neurotechnology that records the activity of individual brain cells via an implanted sensor the size of a baby aspirin.........

Psychiatric symptoms in children with epilepsy

A newly published report reveals that children with epilepsy are more likely to have psychiatric symptoms, with gender a determining factor in their development. Findings showed that girls had more emotional problems, while boys had more hyperactivity/inattention problems and issues regarding peer relationships. Details of this study in Norwegian children are now available online in Epilepsia, a journal published by Wiley-Blackwell on behalf of the International League Against Epilepsy.

Prior studies have shown that children with epilepsy are at increased risk of developing behavioral problems and psychiatric disorders including anxiety, depression, and attention-deficit/hyperactivity disorder (ADHD). In a 2003 population-based study, psychiatric disorders were reported in 37% of children with epilepsy, while children with diabetes and those in the healthy control group were much lower at 11% and 9%, respectively (Davies et al., 2003). Medical evidence, however, has not clearly established when children or teens with epilepsy appears to be vulnerable to developing psychiatric issues, or how gender influences psychopathology in epilepsy.

The current study used data collected by the Norwegian Health Services Research Centre in a 2002 health profile questionnaire. For children in the 8-13 years of age group, there were 14,699 (response rate of 78%) parents who completed the questionnaire which included questions on topics such as sociodemographic conditions, physical and mental health, and psychosocial conditions. To assess psychiatric symptoms, scientists used the parent report of the Strengths and Difficulties Questionnaire (SDQ) which included questions covering four problem domains�emotional symptoms, conduct problems, hyperactivity-inattention, and peer problems�and prosocial behavior. The SDQ scores were classified as normal, borderline, or abnormal.........

Major clue in long-term memory making

Image shows the formation of dendritic spines during long-term potentiation in a single synapse. Signaling activity is color coded (red = high activity of Cdc42, blue = low activity). Activity is high only in the growing spine, and this shows Cdc42 helps to strengthen a synapse for long-term memory storage.

Credit: Ryohei Yasuda, Duke University Medical Center

You may remember the color of your loved one's eyes for years. But how?.

Researchers think that long-term potentiation (LTP) � the long-lasting increase of signals across a correlation between brain cells -- underlies our ability to remember over time and to learn, but how that happens is a central question in neuroscience.

Scientists at Duke University Medical Center have found a cascade of signaling molecules that allows a commonly very brief signal to last for tens of minutes, providing the brain framework for stronger connections (synapses) that can summon a memory for a period of months or even years.

Their findings about how the synapses change the strength of connections could have a bearing on Alzheimer's disease, autism and mental retardation, said Ryohei Yasuda, Ph.D., assistant professor of neurobiology and senior author.

"We observed that a biochemical process that lasts a long time is what causes memory storage," said Yasuda, who is a Howard Hughes Medical Institute Early Career Scientist.

This work was reported in the March 20 issue of Nature

The scientists were investigating the signaling molecules that regulate the actin cytoskeleton, which serves as the structural framework of synapses.

"The signaling molecules could help to rearrange the framework, and give more volume and strength to the synapses," Yasuda said. "We reasoned that a long-lasting memory could possibly come from changes in the building block assemblies."........

Managing post-stroke depression

Arlene A. Schmid, Ph.D., is a Regenstrief Institute investigator, an assistant professor of occupational therapy at the IU School of Health and Rehabilitation Science and a VA Center of Excellence on Implementing Evidence Based Practice investigator.

Credit: Regenstrief Institute

Usage Restrictions: Photo credit to Regenstrief Institute

Stroke patients who are not successfully treated for depression are at higher risk of losing some of their capability to function normally, as per a research studyin the March 15, 2011 issue of the journal Neurology

Eventhough as a number of as a third of those who experience a stroke develop depression, a newly released study by scientists from the Regenstrief Institute, the schools of health and rehabilitation sciences and of medicine at Indiana University-Purdue University Indianapolis and the Richard L. Roudebush VA Medical Center is the first to look whether managing post-stroke depression improves physical functioning.

They scientists report that individuals who remain depressed three months after a stroke are more likely to have decreased functional capabilities than those whose depression was successfully treated. Functional capabilities include getting dressed, feeding oneself, and accomplishing other tasks. These capabilities increased significantly in those people who were treated for depression.

Post-stroke depression may be associated with chemical changes in the brain, clinical evidence indicates.

"The relationship between post-stroke depression and recovery of function after a stroke has not been well understood. Prior scientists have looked at both depression and function after stroke but they did not investigate whether identifying and managing depression improved ability to accomplish tasks of daily living and other function related issues," said study first author Arlene A. Schmid, Ph.D., a Regenstrief Institute investigator, an assistant professor of occupational treatment at the IU School of Health and Rehabilitation Sciences and a VA Center of Excellence on Implementing Evidence Based Practice investigator.........

Did you know?The drug Ativan is better than Valium or Dilantin for controlling severe epileptic seizures, according to a new review of studies.Ativan, or lorazepam, and Valium, or diazepam, are both benzodiazepines, the currently preferred class of drugs for treating severe epileptic seizures. Dilantin, or phenytoin, is an anticonvulsant long used for the treatment of epileptic seizures.